Coated sling material

ABSTRACT

The present invention relates to a sling, methods of making and using a sling, and kits comprising a sling for treating urinary incontinence. The sling has multiple elongation properties that serve to improve the support of the urethra. The sling may comprise a coated material adapted for urethral suspension. The coated sling has properties that appear to enhance the sling elongation characteristics. The coated sling further includes properties that reduce its susceptibility to bacterial infections. The sling further includes properties to enhance the proper tensioning of the sling.

CLAIM OF PRIORITY

[0001] This application claims priority to U.S. Provisional PatentApplication No. 60/230,647, filed Sep. 7, 2000.

FIELD OF THE INVENTION

[0002] The present invention generally relates to the repair of tissuedefects in a patient, including such defects as hernia. The presentinvention specifically relates to devices and methods in the long-termcure of recurrent female urinary incontinence. More particularly, thepresent invention relates to slings for use in treating female urinaryincontinence and methods of making and using the slings.

BACKGROUND OF THE INVENTION

[0003] Normal urination and continence is dependent upon normal functionof the urinary tract, kidneys and nervous system. In addition, in women,continence requires correct coaptation and urethral support.Specifically, in order for continence to be maintained, the urethra mustbe supported and stabilized in its normal anatomic position behind thepubic bone, adjacent to the vaginal wall. The natural support system forthe female urethra is a layer of support composed of pelvic and vaginalwall tissue and ligaments, which attach to the pubic bone. Relaxation,weakening or loss of this support system results in hypermobility of theurethra and bladder to an unnaturally low position within the pelvis.This defect contributes to about 30% of incontinence in women.

[0004] One form of incontinence, referred to as stress incontinence, isan involuntary loss of urine that occurs with increased abdominalpressure such as with coughing, sneezing, laughing, or lifting. Urethralhypermobility may be a result of pregnancy (one reason why stressincontinence is common in women who have had multiple pregnancies), ormay be due to pelvic prolapse. In pelvic prolapse, there is a protrusionor falling of the bladder, urethra, or rectal wall into the woman'svaginal space. Additionally, in women with low estrogen levels such asin post-menopausal females, stress incontinence is more likely to occurdue to decreased vaginal muscle tone resulting from the loss ofestrogen.

[0005] Approaches for treating female urinary incontinence vary andinclude methods directed at elevating the urethra or the bladder neck(upper region of the urethra) to return it to its normal anatomicalposition behind the pubic bone. These methods include needle suspensionprocedures and sling procedures. The needle suspension procedure is acommonly used procedure which involves placement of sutures in thesupport tissue (fascia) on either side of the displaced urethra andattaching these sutures to fixed sites such as bone and soft tissue.Therefore, a variety of devices have been developed to aid in the fixedattachment of the sutures to the support structures. A disadvantage withthis approach, however, is that the tissue support structures being usedfor the urethra are themselves stretched or otherwise deficient,thereby, making them inefficient as support structures and a lesseffective solution.

[0006] Another approach for treating female incontinence is the slingprocedure. In this procedure a sling is formed by taking a piece ofhuman abdominal tissue (fascia) or a piece of synthetic material andusing this as a platform to provide support and/or restore the urethrato its normal retropubic position. Slings made of biological tissuerequire either growing or harvesting autologous tissue or usingprocessed cadaveric tissue. Therefore, these types of sling materialsare sometimes undesirable in that they increase the expense, surgeon'stime required and complexity of the procedure.

[0007] As an alternative to human tissue, prefabricated or syntheticslings have been developed for use in treating incontinence and aredescribed, for example, in U.S. Pat. No. 6,042,534. These slings aresaid to offer improvements to the sling procedure for treatingincontinence in that the synthetic slings are supplied to the physicianin shapes and dimensions adapted for urethral stabilization. Thiseliminates the need for sizing of the sling material by the surgeonduring surgery, which greatly reduces the time required for the surgicalprocedure.

[0008] Another example of a synthetic sling and system for use intreating incontinence is described in U.S. Pat. No. 6,039,686 issuedMar. 21, 2000 to Kovac. The sling system of Kovac involves stabilizingthe urethra using a mesh sling having an innovative mesh suturingpattern that is secured in vivo by short sutures attached to theposterior/inferior (lower, back) portion of the pubic bone instead ofthe superior (upper) portion of the pubic bone as with other methods.

[0009] The tissue and mesh used in prior slings can be fabricated orobtained from a variety of materials and sources. There does not appearto be any attention given to configuring, creating or modifying theseslings in a manner to provide optimal elongation characteristics to thesupport tissue. Particular elongation properties are desirable in somecircumstances, such as when the amount of tension or support at theregion immediately surrounding the bladder neck of the urethra isimportant.

[0010] Tissue ingrowth, infection resistance and capacity to erodesurrounding tissue are also factors in sling designs. The specificeffect of the elasticity of the sling on these factors is not known ingreat detail.

[0011] In view of the above, although improvements in surgical treatmentof urinary incontinence have been made, there is a need to provide evenmore improved sling systems so as to further enhance reliability and tobetter respond to patient kinetics.

SUMMARY OF THE INVENTION

[0012] In view of the foregoing, it is an object of the presentinvention to provide a surgical sling that addresses the limitations anddisadvantages associated with prior devices and systems, yet meets theneeds of the user.

[0013] A further object of the invention is to provide a sling apparatushaving distinct elongation properties along its length and its width andthat minimizes the complexities of the placement procedure for thesurgeon.

[0014] A further object of the invention is to provide a surgical slingfabricated such that it has one elongation property in one direction anda second elongation property in a second direction.

[0015] An additional object of the invention is to provide a coating toa sling material that contributes to appropriate elongation property,improves biocompatibility and inhibits or resists infection.

[0016] An additional object of the invention is to provide a method ofmaking and using a multiple elongation sling system for treatment ofurinary incontinence. The system can include a surgical sling havingseveral distinct elongation properties and adapted to be passed underthe urethra for supporting the urethra in its normal anatomic position.When inserted into a patient, the sling can also prevent abnormalurethral descent in a patient.

[0017] An additional object of the invention is to provide a slingmaterial made from a mesh wherein the mesh is coated but contains openholes or pores to promote tissue in-growth.

[0018] An additional object of the invention is to provide a slingmaterial that provides visual indicia to the user that is indicative ofa particular tensioned state of the sling material.

[0019] The present invention includes coated slings and slings havingcertain physical and biologic characteristics that increase the overalleffectiveness and comfort of the sling once implanted in vivo. Suchsystems also include slings that provide visual indicia to the userindicating when the sling has been manipulated into a desired state,e.g., into a desired tension.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020]FIG. 1 is a view of an uncoated base material for use as a slingin accordance with one embodiment of the invention;

[0021] FIGS. 2A-2B are views of a first embodiment of a sling inaccordance with the present invention;

[0022] FIGS. 3A-3B are views of a second embodiment of a sling inaccordance with the present invention;

[0023]FIG. 4 is a flow chart for fabricating a sling in accordance withone embodiment of the invention;

[0024]FIG. 5 is a schematic view of another preferred embodiment inaccordance with the present invention;

[0025]FIGS. 6A and 6B are views of a sling material in accordance withone embodiment of the present invention and a method of determiningtension in accordance with the present invention;

[0026]FIGS. 7A and 7B are views of a sling material in accordance withanother embodiment of the present invention and a method of determiningtension in accordance with the present invention; and,

[0027]FIGS. 8A and 8B are views of a sling material in accordance withanother embodiment of the present invention and a method of determiningtension in accorance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention provides efficient and reliable slings foruse in treating males and females. The sling is particularly suitablefor pelvic floor reconstruction surgery and for treating urinaryincontinence. The features of the invention as described herein providea surgical sling having at least two different elongationcharacteristics along its surface area. In addition, the slings may becoated with, for example, a silicone coating. Such coating is believedto contribute to the desired elongation properties of the mesh, assistwith ensuring biocompatibility, and provide a carrier for anti-microbialagents.

[0029] Referring to FIG. 1, an enlarged plan view of a material 10according to one aspect of the invention includes a material that is asurgical mesh 12. Individual strands or filaments 14 collectively form amultifilament yarn 16 that can be woven or braided 18 to form thedesired weave. The weave leads to a pattern of holes or pores 24.

[0030] Materials suitable for use in fabricating the coated slings ofthe present invention include man-made materials such as filamentousmesh materials. Filamentous mesh materials include synthetic fibers suchas polyester, polyurethane, nylon, or polypropylene which can be wovenor braided to form a mesh 12. The filaments in such materials may beoriented in a single direction or may be multidirectional.

[0031] As will be further described below, the pattern formed by theweave can be designed so as to provide a mesh material havingdirectionally oriented elongation properties. In a preferred embodimentof the present invention, the mesh material comprises a weave patternwhere the holes 24 have a diamond shape. As would be apparent to oneskilled in the art, the degree of “stretch” or elongation properties ineither direction of the mesh pattern can be adjusted as preferred by auser by altering the weave of the mesh material.

[0032] In a preferred embodiment, a synthetic filamentous materialsuitable for fabricating a mesh for use as a sling include acommercially available material comprised of a Rashel knit mesh madefrom 150 denier polyester yarn. Such a mesh has a hole size ofapproximately {fraction (1/32)}″ (0.794 mm) and a weight ofapproximately 4.7 oz/yd. (133.25 gr/0.914 m). The yarn is amulti-filament yarn. In another embodiment a mesh know as Mersilene™ maybe used.

[0033] The weave of the mesh according to one aspect of the invention issuch that it has greater elongation properties in one direction 20 thanit does in a second direction 22 transverse (or perpendicular) to thefirst direction 20.

[0034] In a preferred embodiment wherein the mesh is cut in arectangular, sling-like configuration, the elongation properties of themesh in the longitudinal direction are such that the mesh will elongatein the range of about 24%-28% beyond its normal state when placed intension by a 20 lb. (9.072 kg) load. The elongation properties in adirection transverse (i.e., perpendicular) to the longitudinaldirection, that is, in the latitudinal direction, are such that the meshwill elongate in the range of about 65% -75% beyond its normal statewhen placed in tension by a 20 lb. (9.072 kg) load.

[0035] By virtue of the longitudinal direction having lesser elongationproperties than the latitudinal direction, there is less tendency forthe longitudinal edges of the sling to curl in on themselves when thesling is in tension along the longitudinal direction. This is a desiredproperty along the longitudinal direction of the mesh insofar as animplanted sling that becomes curled in this manner can be more prone tocause tissue irritation and ultimately tissue erosion in the patient.

[0036] Conversely, by virtue of the latitudinal direction of the meshsling having greater elongation properties, the sling provides greaterflexibility and “give” in a direction parallel to the urethra. As aresult, the sling can still serve its function of treating incontinencebut it does so with less trauma and greater comfort since the sling isnow more responsive to patient movements and activities.

[0037] These desirable properties of the mesh are particularly acute insling operations where the sling is attached to the pubic bone at thesling's opposite longitudinal ends. That is, the properties of theinvention are best utilized when the sling is attached to opposite sidesof the pubic bone and placed in tension along its longitudinal axis. Inthis manner, elongation is allowed in the longitudinal direction withminimal edge curling while at the same time the elongation is enhancedin the latitudinal direction to promote responsiveness to patientmovement. This result is believed to make the sling procedure a moreclinically stable procedure that improves patient comfort.

[0038] Alternatively, in some surgical procedures, the sling may beplaced in the body in a tension free rest position. Even in this tensionfree rest position, the sling according to the present invention isbelieved to resist edge curling when anatomical movement (e.g. a stressevent such as a cough) places tension on the sling.

[0039] As depicted in FIGS. 2A-3B, the present invention furthercontemplates a sling wherein the above-described mesh material is coatedwith a substance to enhance its properties and, in some cases, provide aplatform for the impregnation of therapeutic substances (drugs,antibiotics, etc.). One such coating may be silicone. In particular,when the material of the sling is constructed of individual yarns thathave the potential for tissue ingrowth, the silicone 30 substantiallycoats the exposed surfaces of the yarns and fills in irregular surfacesof the yarns of the mesh material and between individual yarns of themesh, thereby substantially preventing in-growth of tissue into thefibers of the yarn of the sling material. Minimizing the exposed surfacearea also reduces the ability of bacteria or microbes to reside withinthe mesh material if the sling is exposed to bacteria during theimplantation procedure. This is particularly advantageous as itdecreases the risk of infection to the patient following implantation ofthe sling. This also restricts bacterial ingrowth into and between anyfibers of the yarn, thereby further resisting infections.

[0040] As is evident from the figures, the coating is applied in amanner such that the holes or pores 24 of the mesh remain open and clearof silicone. That is, the exposed surfaces within the holes or pores 24themselves remain open and free of silicone. As a result, a sling isobtained that resists infection (due to the coating) but also promotestissue in-growth (due to the holes or pores 24).

[0041] A synthetic sling fabric material that is coated with a substancesuch as silicone is also advantageous in that the coating can providelubricating characteristics to the mesh that enables easier adjustmentof the sling during the implantation procedure. Further, the siliconecoating creates in the sling a composite structure of the fabric and thesilicone that better interacts with the patient's tissue. The siliconealso coats the yarn material to the degree that the yarn functions muchlike a monofilament. Such a monofilament is believed to be less prone toinfection. It is also believed to lead to less erosion of the tissue.

[0042] A coating such as silicone provides a platform from whichtherapeutic substances like antibiotics or antimicrobial agents can beintroduced to the patient. Such agents can be impregnated into thesilicone coating or, alternatively, may be formulated with thecomposition comprising the silicone coating and applied during thecoating procedure. In some embodiments, a silicone coating containing orimpregnated with antibiotic agents may contain a drug that is formulatedto be time-released. Examples of agents suitable for use includeantibiotics and antimycotics such as, gentamicin, fungizone, rifampin orminocycline HCL. Other agents may also be incorporated in the silicone,such as, but not limited to antiseptic agents, radioopaque agents andother antimicrobial agents.

[0043] In a preferred embodiment of the invention, the coating of thesling will also impact the dual elongation properties of the sling. Forexample, the fabric mesh discussed previously, which is later coatedwith silicone, will result in a mesh that elongates in its longitudinaldirection about 19.5%-21.5% beyond its normal state when placed intension at about 20 lbs. (9.072 kg) of force. Conversely, the meshelongates in its latitudinal direction about 120%-130% beyond its normalstate when placed in tension at about 20 lbs. (9.072 kg) of force. Thisis a desired result insofar as elongation properties are tending to beenhanced in the latitudinal direction (to provide patient comfort) butare tending to be minimized in the longitudinal direction (to reduce anycurling propensities).

[0044] In this preferred embodiment, the reduced elongation propertiesin the longitudinal direction are believed to have been achieved as aresult of holding the mesh in tension in the longitudinal direction atthe time the mesh was coated. In other words, it appears thatpre-stretching, or at least pre-tensioning the mesh in the longitudinaldirection during the coating process, led to the reduction in elongationproperties in the longitudinal direction as compared to the elongationproperties in the longitudinal direction in the uncoated mesh sling. Asa result, it is contemplated as part of the invention, that, should itbe desired to avoid reduction of the elongation properties in thelongitudinal direction, the mesh should not be held in tension along thelongitudinal direction and perhaps should be held free of tensionaltogether, or in uniform tension, or in tension along the latitudinaldirection prior to silicone coating.

[0045] In this regard, a number of tests have been performed to morefully expand the explanation and implementation of the presentinvention. These tests involve the acquisition of data on the elongationproperties of the sling according to how the sling has been processedwith a silicone coating. The result of the tests are set forth in thefollowing table. TABLE A Si Coated w/ Si Coated w/ 5 Lb test Si Coatedw/o Longitudinal Latitudinal load Uncoated Pre-Tension Pre-TensionPre-Tension Longitudinal  8% 5% 2.5% 10.5% Elongation Latitudinal 36%N/A  65%   25% Elongation

[0046] As is evident from the table, there were four types of slingsthat were tested, namely: (1) an uncoated sling; (2) a sling that wasnot held in tension while being coated with silicone; (3) a sling thatwas held in longitudinal tension while being coated with silicone; and,(4) a sling that was held in latitudinal tension while being coated withsilicone. As is also evident from the table, each of the four slingswere tested for respective elongation properties both in thelongitudinal direction and the latitudinal direction. These tests wereconducted using a 5 lb tension-loading device.

[0047] The resulting data is consistent with the elongation figuresdiscussed previously. For example, when the sling is coated withsilicone while under longitudinal tension, there is a dramatic decreasein longitudinal elongation properties in the resulting sling accompaniedwith a dramatic increase in latitudinal elongation properties in thesling as compared to the corresponding elongation properties of anuncoated sling. In addition, a sling coated with silicone underlatitudinal tension leads to a sling having increased longitudinalelongation properties accompanied with reduced latitudinal elongationproperties. As a result, it can be seen that desirable elongationproperties that would otherwise not be available under normal conditionscan be “locked” into the sling during the coating process.

[0048] One embodiment of the invention that is particularly exemplary ofa manner in which to exploit the invention is set forth in FIG. 5. Inthis embodiment, a sling 500 is provided that has different elongationproperties at different regions or zones on the sling. These regions area result of molding separately manufactured strips or portions of coatedfabric into a single sling 500.

[0049] For example, in one embodiment, the central region 502 of thesling 500 has been coated with silicone while in latitudinal tensionthus giving this central region 502 a somewhat increased longitudinalelongation property and a somewhat decreased latitudinal elongationproperty over a non-pretensioned coated sling (see Table A).

[0050] The intermediate regions 504 of the sling 500 have been coatedwith silicone while in longitudinal pre-tension, thus giving theintermediate region 504 a dramatically decreased longitudinal elongationproperty and a dramatically increased latitudinal elongation propertyover a non-tensioned, coated sling. Moreover, the intermediate regions504 may molded into place to form the sling in a transverse direction(i.e., rotated 90°) as compared to the configuration of the fabric inthe central region 502. As a result the longitudinal and latitudinalelongation properties exhibited by these intermediate regions 504 of thesling 500 actually correspond to the latitudinal and longitudinalproperties, respectively, set forth in Table A for the sling that wassilicone coated while in longitudinal tension.

[0051] The end regions 506 of the sling 500 have been coated withsilicone while in longitudinal tension thus giving the end regions 506 adecreased longitudinal elongation property and an increased latitudinalelongation property (see Table A). The end result is a sling 500 thatprovides varying elongation properties along the length of the sling 500that can be best suited to mitigate undesirable curling tendencies ofthe sling while enhancing the desirable flexibility characteristics ofthe sling.

[0052] Although the aforesaid embodiment is disclosed as comprisingdiscrete portions of coated fabric that are molded into a completesling, this aspect of the invention is not so limited. For example, itis within the scope of the invention to create a similar “multi-zone”sling merely by coating various regions or zones of a unitary slingunder differing tension parameters at these various regions or zones.

[0053] In view of the above disclosure, it will be seen that the dualelongation properties of the invention as well as the coating by asubstance such as silicone, enhances and improves the efficiency of thesling when placed in the patient. Furthermore, the coating and method ofcoating improves the lubricity between the mesh and the tissue and alsoappears to enhance the elongation properties of the sling. In otherwords, a sling in accordance with the present invention provides theneeded long term support for effectively stabilizing the urethra to itsnormal anatomical position while also permitting temporary movement ofthe urethra (due to the dynamic nature of the patient's anatomy andmovements) with the pelvis.

[0054] Depending upon the parameters of the coating process used,varying degrees of silicone thickness surrounding the mesh yarns can beobtained. However, in all circumstances, the holes or pores 24 remainopen after coating. Referring to FIGS. 2A, 2B, 3A and 3B, depending uponthe desire or need of the user, a sling can be coated so as to comprisea coated mesh material having a thickness ranging from about 0.024inches (0.61 mm) to about 0.036 inches (0.914 mm) (FIGS. 3A, 3B) or fromabout 0.020 inches (0.508 mm) to about 0.025 inches (0.635 mm) (FIGS. 2Aand 2B). In one embodiment, the thickness of the sling material in theuncoated state is about 0.020 inches (0.508 mm) plus or minus about0.002 inches. In a preferred embodiment, the size of the holes or pores24 after coating is preferably in the range of about 0.040 inches (1.016mm) to about 0.055 inches (1.397 mm).

[0055] In a preferred embodiment, a silicone-coated sling will have agenerally rectangular shape that is approximately 2-12 cm wide (morepreferably 10 cm) and 5-20 cm long. In particular, a silicone-coatedsling of the present invention will be of sufficient size and dimensionso as to pass behind the urethra and support the urethra in its normalanatomic position when implanted in vivo. In addition, thesilicone-coated sling should be adapted so as to be capable ofpreventing abnormal urethral descent under increased intra-abdominalpressure.

[0056] It is contemplated that the present invention can be used with avariety of sling systems and methods for treating urinary incontinence.For example, a coated sling in accordance with the present invention,can be used with the system for the long term cure of recurrent urinaryfemale incontinence as described in co-pending U.S. patent applicationSer. No. 09/236,212 filed Jan. 1, 1999 (Kovac), entitled “System andMethod for Treating Female Urinary Incontinence,”) the entire disclosureof which is hereby incorporated by reference. When used in such asystem, a silicone-coated sling can be installed in vivo using thevaginal installation procedure as described in the application.Alternatively, a coated sling in accordance with the present inventioncan be prefabricated according to the dimensions and shapes asdescribed, for example, in U.S. Pat. No. 6,042,534 issued Mar. 28, 2000entitled “Stabilization sling for use in minimally invasive pelvicsurgery” and installed as described in U.S. Pat. No. 6,042,534. A coatedsling of the present invention can also be installed abdominally orlaparoscopically using procedures well known in the art.

[0057] In addition, sheets of silicone coated fabric may be prepared ina similar manner for general pelvic floor reconstruction.

[0058] Method for Silicone Coating a Sling

[0059]FIG. 4 illustrates one preferred embodiment of a process ofapplying a silicone coat to a mesh material for use as a sling. Themethod includes step 40 of providing a mesh material which can bemanipulated for use as a sling. In a preferred method, a siliconedispersion is selected for use as the coating material. In step 40, apreferred mesh material is as previously described. The siliconedispersion is preferably a medical grade silicone disperstion. Thesilicone dispersion is a result of mixing equal parts (100 g each) of asilicone such as Medium 6820 with 5 parts (500 g) solvent such asXylene. The dispersion can be mixed by stirring on a stir plate in afume hood. Mixing should be performed for a minimum of 20 minutes withthe container covered so as to minimize evaporation.

[0060] Next, in step 50, a container such as an aluminum pan is filledwith the silicone dispersion for immersion of the mesh material. The panshould be kept covered (with foil, for example) when not in use, so asto prevent evaporation.

[0061] In step 60, the mesh material is placed into the dispersion mixand is held flat by use of, for example, 6″ (15.24 cm) embroidery hoops.When using embroidery hoops, the mesh material should be pulled throughthe edges of the hoop until the mesh material is taut, flat, andconstrained along most if not all of the peripheral edges of the meshmaterial. Care should be taken not to inordinately stretch the materialas this could result in distortion of the holes of the mesh material orin uneven coating of the mesh material, which can affect the dualelongation aspect of the sling. The mesh material should be trimmed tobe sized closely to the dimensions of the hoop so as to minimizematerial overlap. The hoop containing the mesh material is placed intothe pan containing the silicone dispersion for about 15 seconds, ormore, and then removed.

[0062] In other embodiments, the sling material can be held in tensionat opposite ends of the sheet prior to applying the coating. Asdiscussed previously, depending on which direction of the mesh is intension during coating, differing elongation properties in the sling maybe obtained.

[0063] In step 70, excess silicone dispersion 42 is removed by allowingthe silicone to drip off of the mesh material as the hoop is placed flatover the pan for about 1-5 minutes.

[0064] In step 80, the coating within the holes of the mesh material arecleared. This can be performed by using a foot-controlled air nozzlehaving an air setting of approximately 55-psi and 600 pulses per minute.Using the air nozzle, the coated mesh material can be continuouslysprayed to clear the openings until there are minimal or no holes filledwith silicone dispersion mix. In one embodiment, the spraying isperformed intermittently. For example, pulsed air may be used.

[0065] In step 90, the coated mesh material is rested, air-sprayed sideup, for approximately 5 to 15 minutes.

[0066] In step 100, the entire procedure outlined above in steps 50-90is then repeated with the exception that the second side of the meshmaterial is now air-sprayed so as to ensure a uniform distribution ofthe silicone coating over all surfaces of the mesh material.

[0067] The spraying steps are performed also to ensure that the holes orpores of the mesh are not filled or closed with silicone. As statedpreviously in one embodiment of the invention, the sling has been coatedwith silicone but still contains open holes or pores to promote tissuegrowth.

[0068] In a preferred embodiment, the entire procedure outlined in steps50-100 is repeated until both sides of the mesh material have 2 coats ormore of dispersion 120. During the repeating process, alternate sides ofthe mesh material may be air-sprayed.

[0069] In step 140, the silicone coating is heated to set the siliconedispersion. This can be performed, for example, by hanging the hoopsholding the mesh in an oven that is set at 160° C. (±10°) for about 20minutes.

[0070] It is noted that the sling according to the present invention maybe constructed using a batch processor a continuous process. Forexample, in a continuous process, the silicone dispersion may be placedin a large reservoir, and the strip material may be provided in anelongate, substantially continuous strip that is substantiallycontinusously fed into the reservoir using, for example, rollers and/ormechanical clamping structures.

[0071] In step 160, the silicone coated mesh material is removed fromthe oven and allowed to cool. Following cooling, the material is thencut from the hoop. If desired, an anti-microbial substance or medicamentcan be impregnated into the silicone elastomer in a subsequent process.

[0072] After removing the material from the hoops, the silicone coatedmesh material can then be fabricated as desired into a sling for use intreating urinary incontinence. As described previously, a siliconecoated mesh material of the present invention, can be used to fabricatea sling such as described in co-pending U.S. application Ser. No.09/236,212, filed Jan. 1, 1999 and then surgically implanted into apatient suffering from urinary incontinence.

[0073] In another embodiment, the sling material is configured in a longnarrow elongated piece of mesh. The width is approximately the samewidth as a sling used in a patient. When coated, the edges of thematerial along the length of the material are coated with the silicone.When an elongated material is used in this manner, all that is requiredto obtain a sling suitable for use in a patient is to cut the elongatedmaterial through its width at the desired length of the sling. This willyield a sling that has the edges along the longitudinal side of thesling completely coated with silicone. In other words, since there is nonecessary cutting in the longitudinal direction (because the material isalready formulated to have the desired sling width) to obtain a desiredsize of sling, the integrity of the coating along the uncut edgesremains intact, thus better ensuring the advantageous propertiesintroduced in the sling as a result of coating.

[0074] A silicone coated sling as described herein can be fabricatedinto a variety of dimensions or can be manipulated to conform to avariety of sling specifications, depending upon user or manufacturer'spreference. In addition, the coated sling can also be adapted so as toinclude structures to aid in the attachment or connection of the slingto the patient in vivo. It is also to be emphasized that silicone isonly one coating that may be used, and, as such, is only exemplary, notlimiting, in the context of the invention.

[0075] In still further embodiments in accordance with the presentinvention, it is desired to enable the user to more easily determine thepresence and magnitude of tension in the sling material during placementof the sling. The ability to accurately make this determination willallow the user to adapt the fixation of the sling in the patient in amanner to maximize the potential of successfully treating theincontinence problem.

[0076] Referring to FIGS. 6A and 6B, a sling material 600 is shown inboth the unstretched, condition (FIG. 6A) and in the tensioned condition(FIG. 6B). This sling material 600 can be comprised of any of the typesand variations of mesh material previously discussed in thisspecification or any other type of mesh material that allows anelongation of the sling when placed under tension.

[0077] When in the unstretched condition (FIG. 6A) the sling 600 has anormal width 602 (e.g., approximately 5 cm) in the central region of thesling 600. When the sling 600 is placed into tension (FIG. 6B), however,the sling 600 takes on a reduced width 604 (e.g., approximately 1 cm) inthe central region of the sling. By virtue of this phenomenon, a meshmaterial having certain known elongation (discussed above) propertiescan be used so that when the sling 600 achieves the reduced width 604, aknown tension thus exists in the sling. Moreover, this known tension canbe selected to exist in the range that is most optimum for treating theincontinence. Furthermore, by using a mesh material in accordance withpreviously discussed embodiments, the optimum tension can be achievedwithout the undesirable curling in the mesh that can cause tissueerosion. In the end, a mesh material is provided that potentiallyminimizes many of the undesirable aspects of placing a sling into apatient while at the same time optimizing the placement so as to enhancethe prospect of successfully treating the incontinence condition.

[0078] Referring to FIGS. 7A and 7B, another embodiment of a sling 700that provides a visual tension indicia is disclosed. In this embodiment,the sling material is fabricated so that there is a geometrical patternin the form of a square 702 visibly evident on the surface of theuntensioned sling 700 (FIG. 7A). However, as the sling is placed intension, the geometrical pattern 702 becomes distorted. Moreover, usingthe known elongation properties of the sling, the sling can befabricated such that when the geometrical pattern achieves a differentknown shape due to tensioning, say, for example, a circle, ellipse orpolygonal structure with one or more arcuate portions (e.g. 702A), thesling will have achieved the desired tension for proper placement in thepatient.

[0079] The invention as disclosed in the embodiment of FIGS. 7A and 7Bis not limited to visual indicia in the form of geometrical patterns.For example, the visual indicia could be a series of seemingly randomlines that, under the target tension, become alligned into a straightline or into a geometrical pattern such as a triangle. As anotherexample, the visual indicia could be a collection of marks or charactersthat, under the target tension, become alligned to spell a word such as“OK,” or “STOP,” or “LIMIT.” In one embodiment the word could even spellthe manufacturer of the sling, such as “AMS.”

[0080] The visual indicia described above could be integrated into themesh material a variety of ways. For example, the mesh could actually beintegrated into the fibers that are woven into the mesh so that theindicia is present upon weaving the material. In another example, thevisual indicia could be added to the mesh as a component of a coating(e.g., silicone) applied to the mesh material.

[0081] Referring next to FIGS. 8A and 8B, an embodiment of the inventionis disclosed wherein the visual tension indicia is in the form ofchanges in the weave of the mesh. For example, a mesh 800 could be usedsuch that it takes on a substantially square hole pattern (FIG. 8A) inthe untensioned condition. Then, when the mesh 800 is stretched the holepattern becomes distorted. Based on the known elongation properties ofthe mesh, the mesh can be manufactured such that a particular desiredtension is present in the mesh when the hole material has changed into adifferent, recognizable pattern. In one embodiment, that new holepattern could be a parallelogram structure as shown in FIG. 8B.

[0082] It will be evident to the reader that the visual tension indiciacomponent of the present invention is not limited to the isolatedembodiments disclosed in the figures and that various combinations ofvisual tension indicia is also contemplated. For example, a mesh using avarying hole pattern indicia as in FIGS. 8A and 8B could be combinedwith either of the visual indicia ideas contemplated in the embodimentsof FIGS. 6A, 6B, 7A and 7B. In the end, the principle to guide the useof indicia is that the user be better enabled to know when a desiredtension has been achieved in the sling by simple visual observation.

[0083] The present invention provides a simple, safe and stable systemfor treating urinary incontinence. The invention, as described herein,with reference to preferred embodiments, provides a coated sling thatsupports an abnormally distended urethra to effectively remedy urinaryincontinence.

[0084] Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

[0085] All publications and patent applications in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated by reference.

What is claimed is:
 1. A sling for insertion into a patient comprising:a surgical sling adapted to support the urethra in its normal anatomicposition and to prevent abnormal urethral descent under intraabdominalpressure; said surgical sling comprising a length of material having alongitudinal axis, and a latitudinal axis; wherein said material has afirst elongation property along said longitudinal axis, and a secondelongation property along said latitudinal axis. said first and secondelongation property being different from each other.
 2. The sling as setforth in claim 1, wherein said second elongation property is greaterthan said first elongation property.
 3. The sling as set forth in claim1, wherein said first elongation property is approximately 8% elongationbeyond a normal state of said sling material when said sling material issubjected to a tension of approximately 5 lbs.
 4. The sling as set forthin claim 3, wherein said second elongation property is approximately 36%elongation beyond a normal state of said sling material when said slingmaterial is subjected to a tension of approximately 5 lbs.
 5. The slingas set forth in claim 1, wherein said first elongation property is inthe range of approximately 24%-28% elongation beyond a normal state ofsaid sling material when said sling is subjected to a tension ofapproximately 20 lbs.
 6. The sling as set forth in claim 5 wherein saidsecond elongation property is in the range of approximately 65%-75%elongation beyond a normal state of said sling material when said slingis subjected to a tension of approximately 20 lbs.
 7. The sling as setforth in claim 1, wherein said sling is coated with a substance thatenhances biocompatibility.
 8. The sling as set forth in claim 7, whereinsaid material comprises a surgical mesh material.
 9. The sling as setforth in claim 8, wherein said substance is silicone.
 10. The sling asset forth in claim 9, wherein said coated mesh has a thickness withinthe range of approximately 0.024″ (0.61 mm) to 0.036″ (0.914 mm). 11.The sling as set forth in claim 7, wherein said material is impregnatedwith therapeutic agent.
 12. The sling as set forth in claim 7, whereinsaid first elongation property is in the range of approximately19.5-21.5% elongation beyond a normal state of said sling material whensaid sling material is subject to a tension of approximately 20 lbs. 13.The sling as set forth in claim 12 wherein said second elongationproperty is in the range of approximately 120-130% elongation beyond anormal state of said sling material when said sling material is subjectto a tension of approximately 20 lbs.
 14. The sling as set forth inclaim 7, wherein said first elongation property is approximately 2.5%elongation beyond a normal state of said sling material when said slingmaterial is subject to a tension of approximately 5 lbs.
 15. The slingas set forth in claim 7, wherein said second elongation property isapproximately 65% elongation beyond a normal state of said slingmaterial when said sling material is subject to a tension ofapproximately 5 lbs.
 16. The sling as set forth in claim 7, wherein saidfirst elongation property is approximately 10.5% elongation beyond anormal state of said sling material when said sling material is subjectto a tension of approximately 5 lbs.
 17. The sling as set forth in claim7, wherein said second elongation property is approximately 25%elongation beyond a normal state of said sling material when said slingmaterial is subject to a tension of approximately 5 lbs.
 18. A method ofmaking a sling for treating urinary incontinence comprising: providing amesh material suitable for constructing a sling for supporting aurethra, said mesh having a first elongation property in a longitudinaldirection and a second, different, elongation property in a latitudinaldirection; providing a coating dispersion; coating said mesh materialwith said coating dispersion; and manipulating said mesh material duringsaid coating so as to create a predetermined value for said first andsecond elongation properties in said mesh material.
 19. A method as setforth in claim 18, wherein said coating is performed using a siliconedispersion.
 20. A method as set forth in claim 18, wherein said meshmaterial is held in pre-tension in a longitudinal direction during saidcoating.
 21. A method as set forth in claim 18, wherein said meshmaterial is held in pre-tension in a latitudinal direction during saidcoating.
 22. A method as set forth in claim 18, wherein saidmanipulating of said mesh includes holding said mesh in pre-tension. 23.A method according to claim 18, wherein the step of coating said meshmaterial includes the step of continuously coating an elongate strip ofsaid material.
 24. A method according to claim 18 further including thestep of blowing fluid such as air on the coated mesh material.
 25. Amethod according to claim 24 wherein the step of blowing air includesthe step of using pulsed air.
 26. A sling for insertion into a patientcomprising: a surgical sling adapted to support the urethra in itsnormal anatomic position and to prevent abnormal urethral descent underintraabdominal pressure; said surgical sling comprising a length ofmaterial having a longitudinal axis, and a latitudinal axis; whereinsaid sling comprises a plurality of regions along its longitudinal axisand wherein each region contains differing elongation properties from animmediately adjacent region.
 27. A sling as set forth in claim 26,wherein said sling material has a coated central region having anincreased longitudinal elongation property and a somewhat decreasedlatitudinal elongation property as compared to elongation properties ofsaid central region in a normal state.
 28. A sling as set forth in claim27, wherein said sling material has a coated intermediate region oneither side of said central region, each of said intermediate regionshaving a decreased longitudinal elongation property and an increasedlatitudinal elongation property as compared to elongation properties ofeach of said intermediate regions in a normal state.
 29. A sling as setforth in claim 28, wherein said sling material has a coated end regionadjacent each intermediate region, each of said end regions having adecreased longitudinal elongation property and an increased latitudinalelongation property as compared to elongation properties of each of saidend regions in a normal state.
 30. A method of restoring urethralanatomy in a patient suffering from urinary incontinence comprising thesteps of: providing a silicone coated sling, inserting a silicone coatedsling into the patient's pelvic cavity; manipulating said sling so as topass under a central region of the patient's urethra; attaching each endportion of the sling to a posterior/inferior region of a right and aleft pubic bone of the patient; and positioning the sling so as torestore and stabilize the urethra to a position that maintains urinarycontinence by orienting said sling such that said sling has a firstelasticity in a direction spanning across the urethra and a second,different elasticity in a direction along the axis of said urethra. 31.A method according to claim 30 wherein the step of providing thesilicone coated sling includes the step of providing a sling wherein thefirst elasticity is more than the second elasticity.
 32. A methodaccording to claim 30 wherein the step of providing the silicone coatedsling includes the step of providing a sling wherein the firstelasticity is less than the second elasticity.
 33. A method of placing asling in a patient for the treatment of urinary incontinence comprising:inserting a sling into the patient's pelvic cavity, the sling havingindicia capable or indicating tension in the sling; manipulating saidsling such that it passes underneath a central region of the patient'surethra; tensioning said sling until said sling achieves a predeterminedtension as indicated by visual indicia present on said sling; and,securing said sling within said patient.
 34. A method according to claim33, wherein tensioning said sling includes observing visual indicia inthe form of a predetermined width reduction in said sling.
 35. A methodaccording to claim 33, wherein tensioning said sling includes observingvisual indicia having the form of a geometric pattern.
 36. A methodaccording to claim 33, wherein tensioning the sling includes observing ageometric pattern having the form of a distortion in a hole pattern ofthe sling material.
 37. A method according to claim 33, whereintensioning the sling includes observing a geometric pattern in the formof a distorted shape integrated onto the sling.
 38. A method accordingto claim 33, wherein tensioning said sling includes observing visualindicia in the form of words.
 39. A sling suitable for use in a slingprocedure to treat urinary incontinence comprising: a mesh materialhaving a predetermined length and a width; said mesh material havingpredetermined elongation properties; said mesh having a predeterminedvisual indicia present on said mesh corresponding to the presence of apredetermined tension in said sling, said predetermined visual indiciabeing absent from said mesh when said sling is free from tension.
 40. Asling according to claim 39, wherein said visual indicia is apredetermined width of said sling.
 41. A sling according to claim 39,wherein said visual indicia is a predetermined geometrical pattern ofsaid sling.
 42. A sling according to claim 41, wherein saidpredetermined geometrical pattern is a hole pattern in said mesh.
 43. Asling according to claim 41, wherein said predetermined geometricalpattern is a geometrical shape integrated onto said mesh.
 44. A slingaccording to claim 39, wherein said visual indicia is a word present onsaid sling.